Glass tempering



'corpration 'of i V rbo, Ohio, `assignotoi Libbeye Owens-Fo'dGiass Company, Toledo, Ohime.

-frhe present irvention` relatesbroadiv to the tempering of giassandmoreparticularly to im provem'ents in the supporting of sheets or *plates of glass during the treatment thereoffi ln th temp'ering of 'g1asssheets according to one known process,- the sheets 3 are first heated to approxi nateiy the point of softening of' the giass and then suddenly cooidto pl'ace the outer surfaces of` said sheet's under cornpressioi and the U interiors thereof under tension; The treatment` of the sheets in this manner;not'oniyrnateriaiiy increases the mechanicai strength' of` the` giass but `further modifies its breaking characteristics i m that,` whengbroken; the glass sheet will disintegrate into "innumerable email andkreiativly harmiess particies instea d` of breaking' into 'large avoided; i Brietiy; this is accompii'shed by t rm- `ingnotches or indentationsir the upper edge i ofth'giass sheet at those points to be'engaged in the drawing Wherein'flike numeraisare* emt -p1oy`ed to `dsign`ate 1ike-` parte throughout the dangerous pieces or slivers* as is th` daewith w ordinary glass sheetsm m the practice `ofthe above processj the ga s's 5 shets are ordinarily supported in a vertical postion during the itemperinguthereoi, and it'is I customary to 'suspend 'or hang the sheet `from a pluraiity o trelatively small tongs or hooks which engageopposite faces of said sheet near` I\ its u penedge.. The hangirg` of the sheet in this manner is,- thowever; open to' some objection due to thefact .that upon heatingand jsoftening ofthe g1ass,- the weight uoflthe sheet causes a sli'ght vertical stretchngt thereof, particularly at those points which 'are engaged by th'e supportgcustomary to cut the sheetzato the i exact shape desired and` as a consequence the vertical stre'tc'h ing` of the sheet upon tsoftening ther'eof resuited (in the formation of` small protuberances or humps which -projectedheyond the up'per edge `of the sheet;` Thepresencegofthese protuberances re suited intthe` deforming ofjthe surface Outline or c'ontour of` the sheet 'and were highly'objectiony able not only from the standpoint of appearance but also` because they-rendered` the sheet oversize at these` points, sometimes exceedingthe toierance specified by` the customer, resultingtin rejection of the giass. These protuberances would not be so objectionable were it possible to trim the sheet after 'tempering, but glass so ing hooks or tongs. i 1 It has-also*beeniheretofore i i tempered cannot be subsequently cut since any attempt at cutting will causej a complete shatteringof the glass. t t i It is the principaiaim and object of thi invention to eliminate the above objectionable feature by the provision of an improved method'of hangin the glass sheet during the tempering thereof wherebythe formation of such protuberances at the upper edge or the sheet win be i tening which is ordinarily in the neighborhood r by the supporting tongs` to oflset the `vertical Stretch of the sheet at such` points upon softening of the glass. j i" Other objects andadvantage of the invention will become more appajent during the course `of the`-fo11owing` description When taken in connection with the accompanying drawing.

semez e Fg." 1` is` View bf one fornof temperinf ab -"para tus which may be-'empioyed in carrying out *the present invention, the means for heating the 'siass-sheet being 'shown in section and thecool ing 'm'eans in elevation; i

Fie 2 is'` a` side" elevatch. of i the supporting means for the glass sheet;

i Fig; 3 "ish e, View illustrating th manner in e which-the' upperf'edge of the` giasssheetis notched portingtongs; and t i i `Fig. 4 is a similar view' illustrating themanner in which the notched portion of the's'heet are stretched'during tempering. In the formjof tempering apparatus illustrated in mg. 1', the meansfor heatingthe glass sheet's at those points-where it isfengaged by-the sup- .comprises a `frnace designated inits entirety t bythe letter A while the 'means for jsubsequntiy `chiliing or cooling' the sheets is designated generaily `bythe` letter B.' Thecooling means `B is* preferably arranged directly above the'furnace A `so that th giass sheet o, after being heated withinthe `furnace,` 'can be 'transferred directly' -to the cooling means' without anyundue loss of heat and without being adverseiy affecte'd -by atmospheric conditions-during thetransfer.`` The furnace A is preferablyof an electrically heated type and is provided with a top opening H through which the giasssheets o to be treat-` ed` may be inserted and removed. `Any suitable removabie covering may be used for the opening ll as will be readily understood. For the purpose of heating the furnace, electrical heating elements l2 may` be used in conjunction with bame piates !3. By means of any conventional indicatng and control mechanism,the temperature of the furnace can be regulated to-heat the glass sheet io to approximateiy its point of sofof 1250 degrees Fahrenheit for fiat glass.

When the giass sheet lo has been heatedto the desired temperature in the furnace, it is waw' lifted therefrom through the top opening u: and subjected immediately to the action of the cooling means B, said means comprising spaced blower heads |4 and [5 connected by conduits IE and IT respectively to suitable bloWers so that blasts of air can be directed simultaneously upon opposite surfaces of the glass sheet when brought into position between said blower heads. 'Each blower *head is preferably provided with a plurality of nipples l8 through which jets or blasts of air are directed againstthe sheet surf'aces;

It will of course be appreciated that the present invention is notlimited to the use of the specific type of means herendisclosed'r heat-' ing and/or for cooling the glasssheets.

The glass sheet o is supported during the tempering thereof by a pair of -relatively 'small hooks or tongs s and 20 which engage the sheet closely adjacent its upper edge and also adjacent the cpposite ends thereof, said .tongs being car- ;ried by asuitable supporting bar or the like lil.

` By means of the tongs !9 and 211, the `glass sheet :is 'hung or suspended in a vertical position from its upper end .as clearlys'hown in Figs. 1 and 2.

As brought out' above', it has heretoiore been ;customary to cutthe glass sheet before tempering to. the exact shane and size desired and to i suspend the sheet from .tongs engaging the same near its upperedge.

thereof particularly at the'points of support or, in other words, where' the *sheet is, engaged by `thesupporting tongs, resulting in the formation of protuberances cr humps 'prcjectin-g beyond 5;

the upper edge of thelsheet. This is particularly true when the glass sheets are` bent between a Also, that upon heating" V ,of the glas's to its point of softening, the 'weight of the sheetxwould cause a'vertical stretching.

- Fi'g. 4 wherein the upper edge of the notched portion, after being stretched, is indicated at v Hand, as shown, is in substantial alignment with the upper edge 22 of the sheet. By way of example only, it has been found that a notch :four 'inch'es long and having a depth of three-` sixty-Vfourths of an inch at its center is satis-`- 'factory although in large sheets, the depth of *the notch may beas much as three-thirty-seconds ofan inch. i

It is to be understood that' the form of the invention herewith shown and' described :is to 'be taken as the iprefer'red embodiment -o the (same, and .that various changes in the -ishape, size and arrangementcf p'artsmay he resorted to without departing from thespirit 'ofxthe 'invertion or the scope `of .the subjoined claims 1. n the tempering :of --glass` sheets, 'Wherein the sheet is suspended -in ;a ;vertical position :from a ;plurality of tongs -er 'the .like engagng the same nearits :upper edge and first 'heated .and `then suddenl cooled, the method of ,preventing the -ormation ofprotuberances in the .upper edge of 'thezsheet -at those points which 'are engaged by said tongs z comprising *termins depressions of predetermineddpth in ;the 'upper edge of 'the V u sheetdirectly above the-!points of .attachment :of

pair oiconvex and concave mold membersywhile Suspended vertically in the above manner. H mus; whenv --the-glass is-being bent-;thereis a downward `pull at the tongs and especially so when making relatively .deep cross bends.

thetongs with said sheet, .heating :the 'sheet'to approximatelythepcint o s oftening of the glass to cause a vertical 'stretching :of said sheet at 'the 'saidpcints of ;support 'to ;bring 'the depressed positions into ssubstantial alignment with the According to, this invention, the -formation of .the protuberances' referred to 'above 'is 'avoided .by notchin'g or indenting the upper edge'oi. the glass sheet duringthe-.cutting thereof at those :points ;to be engaged by the ;tongs 1-9` and- 20 to ofiset or compen-sate for the 'Vertical stretch of the=sheet;at these points uponsoftening oftthet .gassxand/er `lsending thereof. Thus,` as shown ing-Fig 3, :the :upper -edge lzz of ,the glass'sheet tois formed with a notch 'or indentationa-!Bat' each .point where it isto be 'engaged'by one :of

the tongsi ts eme and upon hanging .thersheet the-'tones se `and -20 engage the sheet near its ;upper edge -ancl substantially intermediate ;the

epposite ende 'of the 'respective *notch ?3 orgin other words,-atthedeepest point therecfl i i 'Upon heating oftheglass tol'its pointoi' Seiteningand/er'during-bending thereof, !the sheet will be stretclted vertically in the same manner as Qheretoore- :at thosepoints where it is engaged 'by thetones.-but thiststretching will notice `sufllupper edge 'of sai-idssheet, and then cooling the said sheet 2. .In :the tempering :o'f glass sheet& wherein the-sheet is suspendedin avertical positicn from a plurality :of tongs or 'the like :engaging the, same neaxits upper edge and :first heated and .then suddenly cnci'ed, ;the'method of preventing the ormation of :prctuberances in the upper j edge Of the-sheetiat those points which -are en`- gaged hys-said.- :tongs comprising zforming depres sions a of greater %length ;than depth in v the upper 'edge cf thegoglass'sheetgbrirging the tongs into erga ement with sheet directly below said depressions and gintermediate the ende thereof, heating-theshte& toapprcximately the point of Seiten-ing of .thesglass to causeavertical stretchingof.: said %sheet at 'the points of er gagernent` of V thetcngs ,theremthl to .bring thedepressed pertions -intosubstantial salignment with 'the' upper edge of said sheet, and then cooling the said sheet.. i

- e .i o GERALD WHITE. 

